Ok, so this time I ran (from linux)
... enter usb mode
* ./flasher-3.5 -F ../RX-51_2009SE_1.2009.41-1.VANILLA_PR_EMMC_MR0_ARM.bin -f -R
... wait for power down, re-enter usb mode
* ../flasher-3.5 -F ../RX-51_2009SE_3.2010.02-8_PR_COMBINED_MR0_ARM.bin -f -R

The flash step throws no errors, looks nice and clean and responsive.

* Go into Applications->settings. Observe settings are in categories ie "Personalization", "Connectivity" etc
* reboot
* Go into Applications->settings. Observe settings momentarily display categories as above, but within 1-2s changes to a single list under extras

Note that I did NOT other stuff with applications, there's no network configuation, so something is quite wrong.

The categorization change is just one symptom. Basically things are broken -- the desktop for example is unresponsive and cannot be scrolled left/right (although once in apps it works ok)

Possibilities?
* My flash was wrong?
* The "gold" eMMC image isn't compatable with the global firmware image
* The global firmware isn't compatable with a UK handset

Possible actions
* Install eMMC + older firmware, check works THEN apply upgrade
* As above, but with UK firmware

Any ideas? This is very strange.